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Children ran screaming from a dance and yoga class “like a scene from a horror movie” to escape a teenager’s savage knife attack that killed two children and wounded 11 other people Monday in northwest England, police and witnesses said.

A 17-year-old boy was arrested on suspicion of murder and attempted murder in the attack in Southport, a seaside town near Liverpool, Merseyside Police said. The motive was not clear, but police said detectives were not treating the attack as terror-related.

Nine children were wounded — six of them in critical condition — in the latest headline-grabbing attack amid a recent rise in knife crime that has stoked anxieties and led to calls for the government to do more to clamp down on bladed weapons.

Two wounded adults who tried to shield the pupils were in critical condition, police said.

“We believe the adults who were injured were bravely trying to protect the children who were being attacked,” Police Chief Constable Serena Kennedy said.

The Taylor Swift-themed workshop was held on the first week of school vacation for children aged about 6 to 11. An advertisement for the two-hour session promised yoga, dance and bracelet making.

Witnesses described hearing blood-curdling screams and seeing children covered in blood.

“They were in the road, running from the nursery,” said Bare Varathan, who owns a shop nearby. “They had been stabbed, here, here, here, everywhere,” indicating neck, back and chest.

U.K. Prime Minister Keir Starmer called the attack “horrendous and deeply shocking.” King Charles III sent his “condolences, prayers and deepest sympathies” for those affected by the “utterly horrific incident.”

Police were called shortly before noon to a street where several small businesses are located behind rows of brick houses in the city of about 100,000.

The first officers who arrived were shocked to find so many casualties from the “ferocious attack,” most of them children with serious injuries, Kennedy said.

Colin Parry, an auto body shop owner, said most of the stabbing victims appeared to be young girls.

“The mothers are coming here now and screaming, Parry said. “It is like a scene from a horror movie. ... It’s like something from America, not like sunny Southport.”

The suspect, who has not been identified, lived in a village about five miles (eight kilometers) from the site of the attack, police said. He was originally from Cardiff, Wales.

Ryan Carney, who lives with his mother in the street, said his mother saw emergency workers carrying children “covered in red, covered in blood. She said she could see the stab wounds in the backs of the children.”

“All this stuff never really happens around here,” he said. “You hear of it, stabbings and stuff like that in major cities, your Manchesters, your Londons. This is sunny Southport. That’s what people call it. The sun’s out. It’s a lovely place to be.”

Britain’s worst attack on children occurred in 1996, when 43-year-old Thomas Hamilton shot 16 kindergarten pupils and their teacher dead in a school gymnasium in Dunblane, Scotland. The U.K. subsequently banned the private ownership of almost all handguns.

Mass shootings and murders with firearms are rare in Britain, where knives were used in about 40 per cent of homicides in the year to March 2023.